The central theme of this proposed SCOR is the role of sodium in hypertension. This is an appropriate theme for this group of investigators and for this particular time in the history of hypertension research. It is appropriate for these investigators because most have had many years of research experience either directly or indirectly concerned with sodium and hypertension. The timing is appropriate because the large backgroud of information available from decades of work indicates that a concerted, multifaceted effort should yield much needed insight into this pervasive problem. The hypertension Task Force of the National Heart, Lung and Blood Institute found, in its review of current knowlege, that questions concerning the role of sodium arose in most subgroup deliberations. The Task Force identified seven research areas that merit particular emphasis.